1. Field of the Invention
The invention relates to the protection of an electrical circuit fed by an alternating current, and more particularly the integration of a fuse into a mobile contactor coupled to an electrical circuit fed by an alternating current.
2. Description of the Relevant Art
A fused circuit breaker is used primarily as a safety device in electrical or electronic circuits. The role of a safety device of this type is to open an electrical circuit with which it is associated when the current flowing through the latter reaches a dangerous intensity, thereby returning this current to a zero intensity. A protection of this type generally guarantees the integrity of the electrical circuit, and more particularly the integrity of the power supply circuit and the restoration into service of the circuit once the fault has been cleared. A circuit breaker thus allows the potentially catastrophic consequences which a lasting overcurrent or short circuit would cause, such as, for example, degradation of the insulators, destruction of the electronic equipment, melting of material or even the start of a fire.
A fused circuit breaker, more simply referred to as a “fuse”, operates through the melting of a fuse element. The melting of the fuse element is caused by the temperature rise due to the overcurrent passing over the fuse. The fuse generally comprises a conductive part, for example a conductive filament or a strip made of a fusible metal or alloy, mounted in an insulating body and connected to two connection pieces. When the current passing over the conductive part exceeds the rating, i.e. the intensity threshold above which the conductive part begins to melt, the conductive part of the fuse melts and opens the circuit.
The insulating body of the fuse may contain air or a material intended to absorb the thermal energy released during the melting of the conductive part. Silica powder or an insulating liquid may thus be used to fill the internal volume of the body. The insulating body is generally implemented in the form of a ceramic or glass laminate cylinder, the ends of which are each provided with a crimped metal bell which is coupled, on the one hand, to the conductive part disposed inside the insulating body and, on the other hand, to a connection tab.
The main disadvantage of a safety device of this type lies in the occupied volume. In the case of a mobile contactor mounted in a reduced space, a safety device of this type cannot be mounted on the contactor without the volume in which the contactor is mounted being changed.